Microbial methane oxidation has a significant impact on the methane flux from marine gas hydrate areas. However, the environmental fate of methane remains poorly constrained. We quantified the relative contributions of aerobic and anaerobic methanotrophs to methane consumption in sediments of the gas hydrate-bearing Sakata Knoll, Japan, by in situ geochemical and microbiological analyses coupled with ¹³C-tracer incubation experiments. The anaerobic ANME-1 and ANME-2 species contributed to the oxidation of 33.2 and 1.4% methane fluxes at 0–10 and 10–22 cm below the seafloor (bsf), respectively. Although the aerobic Methylococcaceae species consumed only 0.9% methane flux in the oxygen depleted 0.0–0.5 cmbsf zone, their metabolic activity was sustained down to 6 cmbsf (based on rRNA and lipid biosyntheses), increasing their contribution to 10.3%. Our study emphasizes that the co-occurrence of aerobic and anaerobic methanotrophy at the redox transition zone is an important determinant of methane flux.

中文翻译：

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同期好氧-厌氧甲烷氧化对天然气水合物区海洋沉积物甲烷排放的影响

微生物甲烷氧化对海洋天然气水合物区域的甲烷通量具有显着影响。然而，甲烷的环境命运仍然受到很少的限制。我们通过原位地球化学和微生物分析以及¹³ C 示踪剂孵化实验，量化了日本含天然气水合物 Sakata Knoll 沉积物中需氧和厌氧甲烷氧化菌对甲烷消耗的相对贡献。厌氧 ANME-1 和 ANME-2 物种在海底 (bsf) 以下 0-10 厘米和 10-22 厘米处分别氧化了 33.2% 和 1.4% 的甲烷通量。尽管需氧甲基球菌科物种在 0.0-0.5 cmbsf 的氧气耗尽区域仅消耗 0.9% 的甲烷通量，但它们的代谢活动持续低至 6 cmbsf（基于 rRNA 和脂质生物合成），将其贡献增加到 10.3%。我们的研究强调，氧化还原过渡区需氧和厌氧甲烷氧化同时发生是甲烷通量的重要决定因素。